Amplitude modulation to assess catheter environment

Abstract

A system may modulate a carrier signal to generate a modulated signal that carries a message for transmission by a first electrode of a catheter. The system may receive an indication of the modulated signal received by a second electrode of the catheter. The system may demodulate the modulated signal received by the second electrode to extract a demodulated message. The system may determine whether the first electrode contacts a target tissue site of a patient based at least in part on the demodulated message.

What is claimed is: 
     
         1 . A system comprising:
 memory;   processing circuitry configured to:   modulate a carrier signal to generate a modulated signal that carries a message for transmission by a first electrode of a catheter;   receive an indication of the modulated signal received by a second electrode of the catheter;   demodulate the modulated signal received by the second electrode to extract a demodulated message; and   determine whether the first electrode contacts a target tissue site of a patient based at least in part on the demodulated message.   
     
     
         2 . The system of  claim 1 , wherein the modulated signal comprises an ablation signal. 
     
     
         3 . The system of  claim 1 , wherein the processing circuitry is further configured to:
 output an indication of whether the first electrode contacts the target tissue site of the patient.   
     
     
         4 . The system of  claim 1 , wherein the target tissue site of the patient is on at least one of:
 an organ tissue, an arterial wall, or a venous wall of the patient.   
     
     
         5 . The system of  claim 1 , wherein to determine whether the first electrode contacts the target tissue site of the patient, the processing circuitry is further configured to:
 compare the demodulated message with the message carried by the modulated signal to determine whether the first electrode contacts the target tissue site of the patient.   
     
     
         6 . The system of  claim 5 , wherein to compare the demodulated message with the message carried by the modulated signal, the processing circuitry is further configured to:
 compare the demodulated message with the message carried by the modulated signal to determine a recovery rate of the message; and   determine whether the first electrode contacts the target tissue site of the patient based at least in part on the recovery rate of the message.   
     
     
         7 . The system of  claim 1 , wherein the processing circuitry is further configured to:
 modulate a second carrier signal to generate a second modulated signal that carries a second message for transmission by the second electrode;   receive an indication of the second modulated signal received by the first electrode of the catheter;   demodulate the second modulated signal received by the first electrode to extract a second demodulated message; and   demodulate whether the second electrode contacts the target tissue site of the patient based at least in part on the second demodulated message.   
     
     
         8 . The system of  claim 7 , wherein the carrier signal has a first carrier frequency and the second carrier signal has a second carrier frequency that is the same as the first carrier frequency. 
     
     
         9 . The system of  claim 8 , wherein the first carrier frequency and the second carrier frequency are in a radio band. 
     
     
         10 . The system of  claim 7 , wherein the message has a first frequency and the second message has a second frequency different from the first frequency. 
     
     
         11 . The system of  claim 10 , wherein the first frequency and the second frequency are separated by a discernable frequency. 
     
     
         12 . The system of  claim 1 , wherein to modulate the carrier signal, the processing circuitry is further configured to:
 modulate an amplitude of the carrier signal to generate the modulated signal that carries the message.   
     
     
         13 . A method comprising:
 modulating, by processing circuitry, a carrier signal to generate a modulated signal that carries a message for transmission by a first electrode of a catheter;   receiving, by the processing circuitry, an indication of the modulated signal received by a second electrode of the catheter;   demodulating, by the processing circuitry, the modulated signal received by the second electrode to extract a demodulated message; and   determining, by the processing circuitry, whether the first electrode contacts a target tissue site of a patient based at least in part on the demodulated message.   
     
     
         14 . The method of  claim 13 , wherein the modulated signal comprises an ablation signal. 
     
     
         15 . The method of  claim 13 , further comprising:
 outputting, by the processing circuitry, an indication of whether the first electrode contacts the target tissue site of the patient.   
     
     
         16 . The method of  claim 13 , wherein the target tissue site of the patient is on at least one of: an organ tissue, an arterial wall, or a venous wall of the patient. 
     
     
         17 . The method of  claim 13 , wherein determining whether the first electrode contacts the target tissue site of the patient further comprises:
 comparing, by the processing circuitry, the demodulated message with the message carried by the modulated signal to determine whether the first electrode contacts the target tissue site of the patient.   
     
     
         18 . The method of  claim 17 , wherein comparing the demodulated message with the message carried by the modulated signal further comprises:
 comparing, by the processing circuitry, the demodulated message with the message carried by the modulated signal to determine a recovery rate of the message; and   determining, by the processing circuitry, whether the first electrode contacts the target tissue site of the patient based at least in part on the recovery rate of the message.   
     
     
         19 . The method of  claim 13 , further comprising:
 modulating, by the processing circuitry, a second carrier signal to generate a second modulated signal that carries a second message for transmission by the second electrode;   receiving, by the processing circuitry, an indication of the second modulated signal received by the first electrode of the catheter;   demodulating, by the processing circuitry, the second modulated signal received by the first electrode to extract a second demodulated message; and   determining, by the processing circuitry, whether the second electrode contacts the target tissue site of the patient based at least in part on the second demodulated message.   
     
     
         20 . The method of  claim 19 , wherein the carrier signal has a first carrier frequency and the second carrier signal has a second carrier frequency that is the same as the first carrier frequency. 
     
     
         21 . The method of  claim 19 , wherein the message has a first frequency and the second message has a second frequency different from the first frequency.